Gas concentration measurement can be provided by means of light absorption, where the absorbed light has an appropriate wavelength or an appropriate range of wavelengths. Oxygen gas is an important gas present, for example, in combustion processes. Residual oxygen detection in combustion processes, for example, yields valuable information for emission monitoring. Furthermore, the measurement of an oxygen concentration in the presence of other gases has abundant applications in the medical field.
In many cases, oxygen concentrations present in an ambient gas may be very low such that a sensitive oxygen concentration measuring device is required.